Question

If an SqlCommand is executed and times out, is the respective SqlConnection closed and/or disposed?

Answer 1

Unless you have your SqlConnection wrapping in a using statement, you’re still responsible for closing and disposing the connection (just like any other exception).

You could also use a try/catch/finally block:

try
{
    // Create and execute your SqlCommand here
}
catch(SqlException ex)
{
    // Catch the timeout
}
finally
{
    // Close and Dispose the SqlConnection you're using
}

But using is much cleaner and disposes automatically:

using(SqlConnection conn = new SqlConnection())
{
    // Do your work here.
    // The SqlConnection will be closed and disposed at the end of the block.
}